What type of beetle is this ?

I used a bacteria waste eliminator. The microbes eat the waste that clogs drains and septics. Bacteria culture, amylase, protease, cellulase and lipase enzymes attack grease, decaying organic matter, etc. Started noticing the flies in my daughters bathroom. They'd work their way into the hallway, but seemed to originate in bathroom. Cleaned her sink drain with brushes, etc. and the same for shower drain. Then used the bio-clean. No more drain flies. Except... They swarm in my attic. Cannot figure this out. They certainly like windows, but I don't have any moist, rotting organic matter for them to hatch and thrive on outside. This all started after we did some work on our house in early winter 2016. This included some plumbing work. Over the winter, the attic smelled funny, almost gassy. That smell is gone, but the cute little drain flies returned. I can't see anything that vents INTO the attic. Only vents to the outside: system vent, and two dehumidifier vents that seem well sealed. HELP!!!!:madhell::madhell::madhell::wall::wall::wall:

I have a rental, 4 stories up. Every year this time the flies get out of CONTROL! I know the garbage cans are a big parts of the problem as there are 4 large ones but the problem is my lower levels dont have the issue and thats where the cans are. Its my top 2. my 2nd floor (which is 2nd from top) texted me and told me he must have killed 20 of them. I have tried moving the cans but everyone just moves them back since they dont want to walk to the bottom of the driveway. I do live by the "if youre not willing to put the effort in then deal with it" but its bothering me why this house gets this every year. Ive had the gutters cleaned to be sure there wasnt anything in them they were nesting in. I dont believe there is anything dead anywhere since I have never found any odors (plus after this many years whatever would have been dead would be LONG decayed), and none of my tenants are dirty. I have sprayed the cans with poison and every year place hanging fly traps (the ones they get in and cant get out) to reduce the numbers. It seems to always pass as quickly as it comes as well. One other detail, the cans are towards the front of the house where as the problem areas are towards the back. anyone have suggestions? thanks one year my 3rd floor said his kitchen window looked like amityville horror so I went by to see it. Sure enough there must have been about 50-100 flies between the glass and screen. I cracked the window slightly and sprayed between until they died and vac'd them out. They never came back that year there. Just perplexing.